The more i read forums like adv and hubb, the more i'm convinced a small bike (250cc-450cc) is better for rtw travel (blend in with the locals, better mileage, easier to handle, cheaper carnet etc etc).
I however have a problem - i'm a tall guy (198/6' 6").

What is a suitable bike or easy to adapt bike in this category for a tall guy like me? Eventual plan is to drive from Europe to SA.

I have a KLR650 but have sat on a KLR250 and it wasn't much lower than the 650 in hieght. It is a simple engine and bike, so repairs wouldn't be an issue. I'm sure there are more modern bikes out there in a higher cc range with better horse power ratios. But if you want to fit in, an older more reliable bike in the smaller cc range like you have stated is probably your best bet. Any bke will take you RTW if you look after it.....it's all personal preferance....nothing else.

You pose a question that has bedeviled many on this site. What bike is reliable, cheap to operate and has adequate comfort for very extended trips. Unlike Willy, I do think there are bikes you should definitely avoid (British singles come to mind as well as some contemporary Chinese bikes -- mechanical companions of very questionable reliability). There are bikes that are known for their RTW qualities (BMW & KTM dual sport singles, KLR 650 & 650 DRs are examples). I would look to one of these since they are built with this sort of extended travel in mind. Anything smaller than 500 c.c. will put more stress on the engine traveling at higher speeds for long distances. You can do it if you are less risk adverse than some people. My cousin bought a used and abused Zundapp 175 c.c. two stroke in India and rode it to the outskirts of Berlin before it finally had a terminal melt down.

I doubt that you, at 6'6", and on a packed motorcycle, would really blend in with the locals. Perhaps. Are you considering making your gear look like crates of chickens, wearing flip flops, torn cheap pants and a worn out Harley T-shirt?

Have you looked at the WR250R? This is a tall bike and I have to say for small FI 250, I'm pretty impressed. I'm 6'4/250lbs by the way. The great thing about the WRR is its 26k mile valve check and 350w stator. That's unheard of on DS bikes. So not only are valve checks far and few between, you can run some pretty decent heated gear on it. IMOP, the WR250R would make a great RTW traveler. For comparison, we have the 2013 Honda CRF250L in our garage and I've spent time on the KLX250S. The WRR has the most powerful motor of these 3 and the FI is top notch, and for a tall guy, its the best fit of the 3 by far. The Honda is probably the most cramped of the 3. The seat to peg height on the Honda feels more like a sport bike than a dual sport, but it works for my wife who only has a 29" inseam.

I've got the Renazco seat on my and setup for me as a tall person and I'm very comfy on it. I actually own a DR650 and my biggest complaint is its so much more cramped compared to the WRR.

If you haven't checked it out, Mark at BigDogAdventures has a pretty good write up on his WRR bulid and he took his to AK and back and basically for the same reasons decided it was a good small light weight adventure bike. - http://bigdogadventures.com/WR250R.htm

IMS makes a 4.75 gallon tank for it too which gives you a nice range. Safari makes a 3.7gal tank.

This is a recent pic of my wife and I next to the CRF & the WRR. She's 5'4" and I'm 6'4". That's the Seat Concepts seat on my WRR in this picture. I was borrowing it from a friend and wasn't that impressed with it. I like my Renazco better.

I'm 6'7" and fir perfectly on my 640 adventure. I have raised bars, and had the suspension correctly built by Race Tech. I'd do a RTW with it no problem. I've ridden it all over the US and Mexico, and I think it's the perfect balance of a great dirtbike, but the comfort and range of a bigger bike.

Air-cooling is basically more simple. But also more primitive. There are reasons, why almost every modern car and motorcycle has water-cooling.

But yeah, some will always prefer to also have carburetors, contact breakers and drum brakes. Just keep in mind, as the bike gets older, everything wears more and more. I'm not so sure that's an advantage for RTW, when spare parts are not easily available, and you'll do most maintenance and fixing yourself.

In short, water-cooling allows to build engines with smaller tolerances, because heat expansion is more controlled.

For RTW, it's not decisive either way, there are proven overlanders with both types of cooling. But nowadays it's getting harder to find new air-cooled machines, and the age of the bike you choose, could be something to think about. How big an issue it is, of course depends on your mechanic skills as well, and if you'll make a total stripdown before the trip, then an older bike could be an ok choice. If you get a newer bike, then that may not be necessary.

Good for you picking a small bike. I've always liked 350 size and notice some "big bike" riders are starting to get the message.

I'm 6'1 and have a big butt, so I sit tall. My DR350SE fits me without modification. I sit at the back of the seat and that gives me plenty of arm and leg room. When I stand the bars are at the limit of my reach. You might need a seat and handlebar raise.

I have the big tank and am going for a better seat soon. Going to raise the front a bit and widen the back, then all will be good.

It is a proven round the world bike. Under 300 lbs, 6 speed, thrifty, reliable. Nice clean examples at $2000

KLR/KLX/SuperSherpa 250 seems to be popular, also

DRZ400 would be my choice if it had a 6-speed. That 6th gear is a miracle, on long trips.

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thetouristThe gate guard glares at me. "It's after curfew." He looks me up and down, "What do you think you are, some kind of ****** tourist?" ..Phu Loi 1969My Idaho =7893

Much as I like the Yamaha WR250R ( I owned a WR250 F and loved it) for its handling and 6 speed box, the biggest drawback I can see for touring is the fuel tank size. The biggest tank Safari make for this bike is 14L. which is not enough for longer rides. EFI is a great idea and is efficient and altitude change friendly, but if it fails and you are in a third world country, it might be hard to fix. I know FCR carbies are not that easy to fix either , but probably more repairable in a low tech workshop.